Good parenting early in life can substantially buffer the negative effects of socioeconomic adversity on children's development. However, we do not know the most cost-effective ways to improve parenting quality among highly stressed, impoverished families of young children, a disproportionate number of whom are African-American (AA). This knowledge gap is compounded by the fact that the evidence-based parenting programs typically used to help low-income families were originally developed and tested on White, middle- class parents. This comparative effectiveness research will test the equivalence of two evidence-based parent training (PT) programs designed to improve parenting quality and reduce behavior problems in young children: Parent-Child Interaction Therapy (PCIT), a well-established, individually tailored PT program considered the gold standard and the Chicago Parent Program (CPP), a novel group-based PT program developed with an advisory board of AA and Latino parents and shown to improve parenting and reduce behavior problems in ethnic minority families living in urban poverty. We will compare the (1) effectiveness of PCIT and CPP for improving parenting behavior and self-efficacy and reducing child behavior problems in a predominantly AA sample of parents seeking treatment for their young children's (2-5 years) behavior problems; (2) perceived social validity of PCIT and CPP based on parent satisfaction, attendance, and treatment engagement; and (3) cost and consequences of PCIT versus CPP related to treatment effect size, clinical costs, and perceived social validity. CPP is hypothesized to yield comparable treatment effects but at less cost and with greater satisfaction. We will also examine differences in PT program effects to determine whether PCIT or CPP is more effective for some families based on the type and severity of child behavior problems and degree of social risk. Using a randomized experimental design, 210 parents/legal guardians and their 2-5 year old children (>80% AA; 97% low-income) referred for behavior problems to a mental health clinic in East Baltimore will be randomized to PCIT (N=105) or CPP (N=105). Data on child behavior problems; and parent discipline, self-efficacy, behavior, stress, and depression will be obtained at baseline and two post-intervention phases. Social risk will be assessed at intake; parent satisfaction, attendance, and engagement will be assessed post- intervention. Clinical costs related to PT and non-PT treatment will be measured monthly. Hypothesis-testing will employ repeated measures MANOVA. This innovative study was designed in collaboration with mental health clinicians employed in the targeted clinical agency to inform implementation, enhance compatibility with current practice, and promote external validity. It will be the first to compare the effectiveness, cost, and social validity of a brief treatment designed with and for ethnic minority parents of young children against a well- established treatment considered to be the gold standard. The long-term goal is to inform the way we invest health care dollars for improving health outcomes for young, ethnic minority children living in urban poverty.